Clip in and rip.

For 2017 RIP 9 RDO 27.5+ 3-Star XT Complete Mountain Bike, Niner took what was arguably the ultimate in trail bikes and threw in some tweaks to push it even further into the all-mountain realm. In doing so, it also ushers in 27.5+ tires, an act of heresy that only makes sense in the Niner genre when you step back and see the similarity in circumference between that classic 29er tire and the smaller-wheeled, yet decidedly donut-sized 27.5+ rabble-rouser. All at once Longer, slacker, and paradoxically more responsive on climbs, the RIP 9's versatile [R]Evolution geometry shreds rock gardens as eagerly as it scales steep grades. This build gets dressed up in Shimano's precisely-shifting workhourse XT drivetrain, a dropper post, and Stan's NoTubes hoops for a whole new level of fun in the dirt.

The frame's versatility is heavily influenced by its Boost axle spacing. By bumping the rear axle out to 148mm, Niner was able to buy enough clearance at the bottom bracket to shorten the chainstays and sharpen the seat tube angle by 11mm and 2.5 degrees, respectively. These subtle changes make the rear triangle that much more responsive to input while also pushing the rider's engine up over the pedals.

The stubby stays also keep the bike agile, but with a 67-degree head tube and 170mm of Lyrik forgiveness up front, it's just as happy to try flattening everything in its path—or at least bailing you out when your lines start to get a bit too ambitious. In the event that discretion wins the day, the RIP 9's longer top tube and short stem keep handling on-point, despite that low head tube angle, so you can always fall back on those dicey stays to navigate stretches of especially techy terrain.

There's obviously a lot of new radness with the RIP 9, but two things remain pleasantly unchanged: the Race Day Optimized (RDO) construction method and the Constantly Varying Arc (CVA) suspension design. RDO involves a dual-compression process that eliminates resin pooling and allows precise control over wall-thickness. Reducing imperfections makes for a more structurally sound frame, and the targeted control over lay-up and wall thickness lets Niner buttress that structure where appropriate and reduce material where it'll save weight without sacrificing stiffness. The result marks the nexus of low weight and efficient durability: a frame that's equal to the abuse of the trail and the pedals.

The new RIP 9's CVA suspension design is also unchanged, but it allows that design to play with 25mm more travel. This brings it up to 150mm and optimizes it for descending fast in hairy terrain while keeping it surprisingly responsive when you get on the gas. Unlike other designs, CVA is optimized for the increased bottom bracket drop inherent in 29ers, so it's well suited to the similar dimensions of a 27.5+ platform. It tends to ride high in the travel with a controlled mid-stroke that balances pedal input and suspension travel, keeping it stable through rock gardens and snappy when you get on the pedals.

The frame's finishing details are everything you'd expect from the obsessive developers at Niner, and our favorite new addition is the inclusion of a BSA threaded bottom bracket. PressFit shells may be lighter and more convenient, but the exact tolerances of a CNC-machined thread are unmatchable by today's composite technology. The threading means bearing cups install perfectly, reducing wear over time and eliminating the creaks and groans that so often accompany PressFit models. Vulnerable frame bits are girded with titanium protection plates, and the frame also includes integrated batter storage in case you get the urge for electro shifting. As a 27.5+ build, the RIP 9 can clear 3in tires; if you'd prefer to restore order to the universe and run it as a 29er, it'll accommodate 2.5in tires.